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Break It Down: Reverse Engineering

cub_reverse_engineering_activity1_figure1_TEDL(Provided courtesy of TeachEngineering)

Level: Students in grades 5-8.
Group Size: 2-3.
Time Required: 90 minutes.

In this lesson for grades 5-8, students learn how the technique of reverse engineering is used to improve technology. Students analyze a push-toy and draw a diagram of the predicted mechanisms inside the toy. They then disassemble the toy and draw the actual inner mechanisms. By understanding how the push-toy functions, students make suggestions for improvement, such as cost effectiveness, improved functionality, ecological friendliness, and any additional functionality they determine is an improvement.

Note: Teachers of older students or those seeking a more complex disassembly lesson might consult this one involving a one-use camera.

LEARNING OBJECTIVES: Engineers learn about technologies, objects and systems through reverse engineering and the engineering design process. By analyzing the structure and function of a device or component, engineers can improve upon the previous design.

After this activity, students should be able to:

  • Define reverse engineering as the process of disassembly and careful analysis with the goal of duplicating or improving a device or component.
  • Demonstrate the process of reverse engineering using a given object or component and suggest areas of improvement.


Each group needs:

  • 2-3 copies of the Reverse Engineering Worksheet, one per student
  • 1 push-toy (available for purchase at or at most toy stores including Toys R Us® or Target®)
  • 1 small Phillips head screwdriver (may be borrowed from other teachers in the school or purchased at Lowe’s® or Home Depot® for under $1 each)
  • 1 small bowl or bin for screws and small pieces

EXPENDABLE COST PER GROUP: US$ 0 (Note: Screw drivers and push-toys are reusable. The push-toy can be purchased for US ~$6.99 each at most toy stores or Screwdrivers can be purchased for under US $1 at most bulk hardware stores.)

KEYWORDS: Reverse engineering, design, re-engineering, engineering design process, engineering design cycle


1. ask questions and state hypotheses that lead to different types of scientific investigations (for example: experimentation, collecting specimens, constructing models, researching scientific literature) (Grades 6 – 8 ) [2007]

2. use appropriate tools, technologies and metric measurements to gather and organize data and report results (Grades 6 – 8 ) [2007]

5. there are interrelationships among science, technology and human activity that affect the world (Grades 6 – 8 ) [2007]

(To check standards of other states, please reference the original lesson plan posted on Teachengineering)

PRE-REQ KNOWLEDGE: Students should understand that engineers use the engineering design process (see Background information under the Procedures section) to invent and improve technologies, objects and systems. In this activity, students focus on the “Asking and Improving” steps in the engineering design process.

By studying an existing engineered object, we can learn a lot about how the object was designed and how it works. What steps might an engineer take to figure out and understand how an existing product works? Usually, we can just take it apart! Engineers use a process called reverse engineering to understand how something functions and to determine ways it can be improved. Have you ever taken something apart to find out what is inside? If you have, the you have already reverse engineered!

By carefully discovering how something was made and how it works, engineers can make suggestions for areas of improvement of the product. Sometimes the improvement is very simple. For example, suppose you reverse engineered a computer hard drive and noticed that one of the screws is not necessary. This may seem like a small detail, but if that screw costs $0.05 and it is removed from 1 million computer hard drives manufactured in 1 year, that saves $50,000. Imagine if you found two screws that were not necessary! A few small changes can make a big difference.

Reverse engineering, however, is not simply taking something apart. This process requires careful observation, disassembly, documentation, analysis and reporting. Many times, the reverse engineering process is non-destructive. This means that the object or component can be reassembled and still function just as it did before you took it apart.

Today, we will practice reverse engineering on a child’s push-toy. Before we take it apart, we will test the toy and then record our predictions of how it works. We will each draw what we think is inside the toy making it work. It is perfectly acceptable to be unsure of the toy’s internal “parts” — just make a reasonable prediction. When everyone is done with their first drawing, we will then carefully disassemble the toy and make notes about the process so we can reassemble it. Throughout the reverse engineering project, we will think of ways this object could be improved. Perhaps there is a way it could function better? Or be manufactured less expensively? We will use our observations to make suggestions for improvement to the child’s toy.


Diagram: A visual representation of a system, process, technique or individual components that make up a part or product; oftentimes is black and white.

Reverse Engineering: The process of taking something apart to understand how it works and suggest improvements.


BACKGROUND: Engineers use the engineering design process to invent and improve technologies, objects and systems.

The engineering design process includes five critical steps:

1. Ask – What is the problem? What have others done?

2. Imagine – What is the best solution? Brainstorm ideas.

3. Plan – Draw a diagram. List the materials you need.

4. Create – Follow your plan and test it out.

5. Improve – How can you improve your design? Go back to Step 1.

Engineers also use the process of reverse engineering to understand existing technologies, objects, components and systems. By carefully disassembling, observing, testing, analyzing and reporting, engineers can understand how something works and suggest ways it might be improved.


  • Gather enough push toys for the class, one for each group of 2-3 students.
  • Make copies of the Reverse Engineering Worksheet, one for each student.
  • Explain to students that reverse engineering is the process of carefully taking something apart to understand how it works and suggest possible areas of improvement.
  • Write the definition of reverse engineering on the board.

With the Students

  • Divide the class into groups of 2-3 students and give each group one push-toy.
  • Tell students to spend about 5 minutes testing the push-toy and to discuss how the toy functions within their groups. Encourage students to consider the mechanisms inside the toy.
  • Hand out one Reverse Engineering Worksheet to each student. Explain that the worksheet contains three sides: the first page is completed before disassembling the toy and the rest is completed after disassembly.
  • Students should complete the first page of the worksheet by drawing their predictions of the inner mechanisms of the toy. Allow enough time (about 15-20 minutes) for students to complete very detailed drawings.
  • While students are working, ask the following questions to the groups:

HOW DOES THE TOY WORK? — What is inside the toy to make it work this way?

  • Be sure the students have completed their initial drawings before handing out screwdrivers for disassembly.
  • Allow groups to begin taking apart the push-toys. Remind all groups to be very careful not to lose any pieces (e.g., small screws, tiny washers, springs, etc.). Instruct student to immediately place all pieces in the small bowl or bin while working; they will be needed for the reassembly.
  • Once the groups are done disassembling the push-toy, have them complete the rest of the worksheet by drawing the actual mechanism.
  • Be sure to leave enough time for students to reassemble the toys.

If push-toys are not available, other objects can easily be substituted. These can be obtained various places, such as garage sales, toy stores, hardware stores, and second-hand stores. Examples include: water toys, audio speakers, coffee maker, combination lock, wind-up toy, toaster, blender, computer keyboard, Etch-a-Sketch™ toy, etc.


Question/Answer: Ask students the following questions and have them raise their hands to answer.

  • As engineers, how do we figure out how something works? For example, suppose we want to know how a toaster works? (Answer: We learn how things work by taking them apart. By doing this, we can figure out what is inside and how it works.)
  • What do you think reverse engineering means? (Answer: Reverse engineering is the process of taking something apart to understand how it works.)
  • Other than learning about how an object functions, what is another goal of reverse engineering? Example? (Answer: Other goals of reverse engineering are to improve the device’s function, make it more cost efficient, make it more ecologically friendly, change the function, or create another use for the object. An example: finding out that one of several screws are not necessary for the performance or durability of a particular product, which winds being hugely cost effective after hundreds or thousands are produced.)

Engineering in Reverse Worksheet: Have students complete the Engineering in Reverse Worksheet and review their answers to determine their understanding.

Post-Activity Assessment
Presentation: Have students discuss the following topics within their groups then assign one topic to each group and have students present their ideas to the class.

  • Describe how the device was disassembled. (Students may explain where the screws were located and how the inside components were taken apart from each other.)
  • What did you learn about the device’s design and function? (Students may explain that the toy is designed to be used by small children, so it is difficult to take apart and is very robust. Also, it contains simple mechanisms which will work for a very long time.)
  • Describe the key components and how they function. (For example, the spring turns the gear which is attached to the wheel axle.)
  • Suggest changes that would improve the device’s function. (Students may explain ways to redesign the toy so that the spring does not get stuck, the toy goes faster, etc.)
  • How could the device be more cost effective to produce? (Students may suggest that fewer screws be used, child-safe glue is used instead of screws, or fewer gears be used.)

Have students create an advertisement (print, video or audio), marketing the re-engineered push-toy to the identified target group. Students should describe the purpose of the object and the improvement(s) they have made.


For lower grades, disassemble one push-toy as a class. This way, younger students will not get frustrated using a screwdriver and losing small parts.

For upper grades, have students reassemble the toy to perform a different function. For example, the reassembled toy must go backwards or must turn in one direction. This will challenge students to really understand how the mechanisms work.

Abarca, Javier, et al. GEEN 1400: First-Year Engineering Projects and GEEN 2830: Innovation and Invention, Third Edition (Spiral Bound), Eds. Janet L. Yowell and Denise W. Carlson. Boulder, CO: Integrated Teaching and Learning Laboratory, College of Engineering and Applied Science, University of Colorado at Boulder, 1999.

Boston Museum of Science, Engineering is Elementary, “The Engineering Design Process,” accessed June 24, 2009.

Contributors: Megan Schroeder, Malinda Schaefer Zarske, Janet Yowell © 2009 by Regents of the University of Colorado. This digital library content was developed by the Integrated Teaching and Learning Program under National Science Foundation GK-12 grant no. 0338326. However, these contents do not necessarily represent the policies of the National Science Foundation, and you should not assume endorsement by the federal government. Supporting Program: Integrated Teaching and Learning Program, College of Engineering, University of Colorado at Boulder

One Response to “Break It Down: Reverse Engineering”

  1. […] Teachers of younger students might try this less involved disassembly lesson using a push […]

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